From: Thomas Gleixner <tglx@linutronix.de>
To: Jiri Kosina <jikos@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Borislav Petkov <bp@suse.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, x86@kernel.org, Greg KH <greg@kroah.com>
Subject: Re: [PATCH] x86/mm: Unbreak modules that rely on external PAGE_KERNEL availability
Date: Wed, 8 Nov 2017 21:47:45 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.20.1711082133410.1962@nanos> (raw)
In-Reply-To: <nycvar.YFH.7.76.1711082103320.6470@cbobk.fhfr.pm>
On Wed, 8 Nov 2017, Jiri Kosina wrote:
> From: Jiri Kosina <jkosina@suse.cz>
>
> Commit
>
> 7744ccdbc16f0 ("x86/mm: Add Secure Memory Encryption (SME) support")
>
> as a side-effect made PAGE_KERNEL all of a sudden unavailable to modules
> which can't make use of EXPORT_SYMBOL_GPL() symbols.
>
> This is because once SME is enabled, sme_me_mask (which is introduced as
> EXPORT_SYMBOL_GPL) makes its way to PAGE_KERNEL through _PAGE_ENC, causing
> imminent build failure for all the modules which make use of all the
> EXPORT-SYMBOL()-exported API (such as vmap(), __vmalloc(),
> remap_pfn_range(), ...).
>
> Exporting (as EXPORT_SYMBOL()) interfaces (and having done so for ages)
> that take pgprot_t argument, while making it impossible to -- all of a
> sudden -- pass PAGE_KERNEL to it, feels rather incosistent.
>
> Restore the original behavior and make it possible to pass PAGE_KERNEL to
> all its EXPORT_SYMBOL() consumers.
To be honest, I fundamentaly hate this, because proprietary crap out there
more or less holds the kernel hostage in its decisions of marking new
functionality GPL only. You have already a choice by disabling SME, but
sure you want to get everything: new features and proprietary stuff.
I fear, that I can't prevent this from being applied, but whoever picks up
that patch, please add:
Despised-by: Thomas Gleixner <tglx@linutronix.de>
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next prev parent reply other threads:[~2017-11-08 20:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-08 20:18 [PATCH] x86/mm: Unbreak modules that rely on external PAGE_KERNEL availability Jiri Kosina
2017-11-08 20:47 ` Thomas Gleixner [this message]
2017-11-08 21:09 ` Linus Torvalds
2017-11-08 21:15 ` Borislav Petkov
2017-11-08 21:23 ` Linus Torvalds
2017-11-08 21:36 ` Tom Lendacky
2017-11-08 21:45 ` Borislav Petkov
2017-11-08 22:04 ` Tom Lendacky
2017-11-08 21:46 ` Linus Torvalds
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